1. Technical Field
The present invention relates to kinematic linkage systems, and more particularly, to a space orientating mechanism that us configured to simulate high maneuvering motion as those performed by high-speed vehicles (ex. aerial vehicles or playground equipment) so as to stimulate its passengers with virtual-but-real and shock-but-exciting feeling, thus being a suitable motion platform or for military fighter trainers or game machines in theme parks.
2. Description of Related Art
Currently the motion platforms, or referred to as space orientating mechanisms, used in flight trainers or amusement rides are mainly 6-axis Stewart platforms and gimbals type multi-ring mechanisms.
The 6-axis Stewart platform was introduced by Stewart and Gough in 1965, which employs six actuators that are fixed to the ground for positioning and posing a top plate. After years of efforts paid to mechanical and kinetic development thereof, Stewart platforms now are well configured in terms of workspace and attitudinal path and thus can avoid singularities. While a Stewart platform can be moved in six degrees of freedom, namely forward/backward, up/down, left/right, roll, pitch and yaw, the maximum extension of the linear actuator or the hydraulic cylinder driving it is substantially limited to the fixed length, causing the moving range of the payload bay highly confined. Particularly, even with optimized design, the three angles, namely the roll angle, the pitch angle and the yaw angle, are still limited to ±45°. Thus, although the 6-axis Stewart platform has been highly developed in these years, its innate insufficiency remains a problem and makes the Stewart platform less useful to simulate high-maneuvering motion in the three-dimensional space as that performed by high-speed vehicles, such as fighter planes and roller coasters, thereby limiting its application scope limited to airline flight training where only smooth take-off and landing are programmed accompanied with occasional interference caused by gusts.
The gimbals type multi-ring mechanism has been developed for a long time. Its multiple rings permit the payload bay it carries to rotate continuously in large angles. However, since such a mechanism lacks for the translational degrees of freedom for up/down, left/right and forward/backward, it is incompetent when talking about stimulating passengers in the payload bay with sudden, scary vibration and shock. In addition, with motors instead of rotary hydraulic cylinders used to output torque, the mechanism having less payload capacity and inefficient inertia would have its application scope significantly limited.
The defect of such a mechanism is out of the fact that its multiple rings are separately configured. In an instance where motors working with gearboxes are employed as the torque output devices for jointly driving a payload bay mounted on the inner ring, the payload bay is bound to the end of the rolling axle of the inner ring. In order to meet the output requirement for the instantaneous maximum angle, the total inertia of the motor and the gearbox must not be small. Even if direct-drive motors are used when the cost forms no concern, they help less in inertia reduction. Therefore, the motor driving the middle ring has to bear the accumulated inertia of the motor-and-gear assemblies of both the payload bay and the inner ring, or it would fail to drive the middle ring to rotate against the pitch axis. Similarly, the motor driving the outer ring has to bear the accumulated inertia of the motor-and-gear assemblies of the payload bay, the inner ring and the middle ring, or it would fail to drive the outer ring to rotate against the yaw axis.
In this context, each of the rings must have significantly increased diameter to contain the corresponding motor and gearbox, resulting in the workspace of the overall mechanism too large and out of proportion to the payload capacity. In addition, difficulty in electric communication can exist between the motors separately pivoted to the rings, and intertwisted wires may hinder the operation of the mechanism. For these reasons, the gimbals type multi-ring mechanism is typically hydraulically driven, making it only suitable for the large multi-axis rolling amusement rides in theme parks, or for the anti-G centrifuge training devices specially designed for military use with less limitation to costs.